Policy hypocrisy

Why does our government engage in preemptive warfare, invasion and occupation of any country it feels like, sell arms to regimes that repress their own people, look the other way when genocide is happening and label those private citizens who attempt to effect regime change in their homelands as terrorists? Is it simply that it is easier to prosecute a few small fish? The hypocrisy is astounding, and I don't see how America will survive as a free state if this continues to be our accepted state of affairs.